1. Technical Field
The present invention relates to a method, and associated structure, for monitoring temperature and temperature distributions in a heating chamber for a temperature range of 200 to 600xc2x0 C., wherein the heating chamber may be used in the fabrication of a semiconductor device.
2. Related Art
Annealing (i.e., heating) a semiconductor wafer at a uniform temperature in a range of 200 to 600xc2x0 C. may be required in a process that fabricates a semiconductor device. In order to ensure that a heating chamber used for the annealing is at the desired uniform temperature, particularly at a local space within the heating chamber at which the semiconductor wafer is positioned, it is necessary to monitor the temperature distribution within the local space of the heating chamber.
There are currently two methods of externally monitoring and calibrating temperature control tools used in the annealing. The first technique employs a monitor having a known thermocouple standard. However, this monitor is difficult to use, time consuming and expensive. Furthermore, this monitor indicates the temperature at only a few isolated locations on the wafer. The second temperature monitoring technique uses a second wafer to indicate the temperature across the entire surface of the wafer being fabricated. Currently, there are thermal oxide wafers that are sensitive in a range of about 800xc2x0 C. to about 1200xc2x0 C. There are also activation monitors implanted with n-type or p-type dopants which are sensitive in a range of about 850xc2x0 C. to about 1100xc2x0 C. Similarly, titanium monitors, which are sputtered with titanium (Ti) and annealed to form TiSi, have a sensitivity in a range of about 650xc2x0 C. to about 750xc2x0 C. Likewise, cobalt (Co) monitors exhibit a sensitivity in a range of about 530xc2x0 C. to about 575xc2x0 C.
Unfortunately, there are no existing temperature monitors having a temperature sensitivity within the range of about 200xc2x0 C. to about 600xc2x0 C. In addition, many of the techniques currently used to monitor annealing temperatures are expensive, time consuming, and difficult to use. Furthermore, none of the above mentioned techniques, with the exception of the thermal oxide monitor, can be reused repeatedly.
Accordingly, there exists a need for a temperature monitoring device for temperatures in the range of about 200xc2x0 C. to about 600xc2x0 C., as well as a need for reconditioning such monitors for repeated usage.
The present invention provides a temperature monitoring wafer, comprising:
a substrate;
a conductive layer coupled to the substrate, wherein the conductive layer includes a conductive material that will oxidize to form a layer of oxide when the conductive material is at a temperature in a temperature range of about 200xc2x0 C. to about and in an oxidizing environment that comprises an oxidizer of sufficient concentration to oxidize a portion of the conductive layer such that the layer of oxide is formed, and wherein said layer of oxide is utilizable for said temperature monitoring.
The present invention provides a method of fabricating a temperature monitoring wafer, comprising the steps of:
providing a substrate; and
forming a conductive layer on the substrate, wherein the conductive layer includes a conductive material that will oxidize to form an oxide layer when the conductive material is at a temperature in a temperature range of about 200xc2x0 C. to about 600xc2x0 C. and in an oxidizing environment that comprises an oxidizer of sufficient concentration to oxidize a portion of the conductive layer such that the oxide layer is formed, and wherein said oxide layer is utilizable for said temperature monitoring.
The present invention provides a method of fabricating a temperature monitoring wafer, comprising the steps of:
providing a substrate;
forming a diffusion barrier layer on the substrate, wherein the diffusion barrier layer inhibits diffusion of a conductive material into the substrate from a conductive layer when the wafer is at a first temperature in a temperature range of about 200xc2x0 C. to about 600xc2x0 C., and wherein the substrate inhibits diffusion of material from the substrate into the conductive layer when the wafer is at a second temperature in the temperature range, and wherein the first temperature and the second temperature are equal or unequal; and
forming the conductive layer on the diffusion barrier layer, wherein the conductive layer includes a conductive material that will oxidize to form an oxide layer when the conductive material is at a temperature in the temperature range and in an oxidizing environment that comprises an oxidizer of sufficient concentration to oxidize a portion of the conductive layer such that the oxide layer is formed, said oxide layer utilizable for said temperature monitoring.
The present invention provides a temperature monitoring device to accurately monitor a temperature distribution in a heating chamber in a 200xc2x0 C. to 600xc2x0 C. temperature range. The present invention also provides a method for reconditioning the temperature monitor for repeated usage. Additionally, the temperature monitor is reliable, easy to use, and inexpensive to fabricate.